Vertical feature growth using fluorine-containing gas

Abstract

A method of vertically growing a material, such as an oxide, on features using a fluorine-containing gas includes performing the following concurrent steps: depositing the material on a relief pattern, such as a mask layer, using a precursor gas and a reactant gas, such as an oxygen-containing gas, and etching side protrusions of the material vertically overlapping recesses using the fluorine-containing gas. The relief pattern includes the features separated by the recesses, which may expose an underlying layer. The method may be performed in situ in an etching chamber of a plasma etching system, such as using a controller operatively coupled to at least one gas source configured to supply the precursor gas, the reactant gas, and the fluorine-containing gas into the etching chamber.

What is claimed is: 
     
         1 . A method comprising performing the following concurrent steps:
 depositing a material on a relief pattern using a precursor gas and a reactant gas, the relief pattern comprising features separated by recesses; and   etching side protrusions of the material vertically overlapping the recesses using a fluorine-containing gas.   
     
     
         2 . The method of  claim 1 , wherein the concurrent steps further comprise:
 applying bias power to a substrate comprising the relief pattern.   
     
     
         3 . The method of  claim 1 , wherein the fluorine-containing gas comprises nitrogen. 
     
     
         4 . The method of  claim 1 , wherein the reactant gas comprises oxygen, and wherein the material is an oxide. 
     
     
         5 . The method of  claim 1 , further comprising:
 performing an etching step using the material as an etch mask to deepen the recesses.   
     
     
         6 . The method of  claim 5 , wherein the concurrent steps and the etching step are alternated as part of a cycle. 
     
     
         7 . The method of  claim 5 , wherein the concurrent steps and the etching step are performed in situ in an etching chamber. 
     
     
         8 . The method of  claim 1 , wherein the relief pattern comprises a metal-oxide resist. 
     
     
         9 . A method comprising:
 vertically growing an oxide on features of a mask layer, the features being separated by openings exposing an underlying layer, wherein vertically growing the oxide comprises concurrently
 depositing the oxide on the features using a precursor gas and an oxygen-containing gas, and 
 etching side protrusions of the oxide vertically overlapping the openings using a fluorine-containing gas; and 
   etching the underlying layer through the openings using the oxide as an etch mask.   
     
     
         10 . The method of  claim 9 , wherein vertically growing the oxide on the features of the mask layer further comprises applying bias power to a substrate comprising the mask layer and the underlying layer concurrently with depositing the oxide and etching the portions of the oxide. 
     
     
         11 . The method of  claim 9 , wherein the fluorine-containing gas comprises a fluoronitrogen compound. 
     
     
         12 . The method of  claim 11 , wherein the fluoronitrogen compound is nitrogen trifluoride. 
     
     
         13 . The method of  claim 9 , wherein vertically growing the oxide and etching the underlying layer are alternated as part of a cycle. 
     
     
         14 . The method of  claim 9 , wherein vertically growing the oxide and etching the underlying layer are performed in situ in an etching chamber. 
     
     
         15 . The method of  claim 9 , wherein the mask layer comprises a metal-oxide resist. 
     
     
         16 . A plasma etching system comprising:
 an etching chamber;   a substrate support disposed in the etching chamber and configured to support a substrate comprising a mask layer disposed over an underlying layer, the mask layer comprising a relief pattern that comprises features separated by openings exposing the underlying layer;   at least one gas source fluidically coupled to the etching chamber and configured to supply a precursor gas, an oxygen-containing gas, and a fluorine-containing gas into the etching chamber; and   a controller operatively coupled to the at least one gas source, the controller comprising a processor and a non-transitory computer-readable medium storing a program including instructions that, when executed by the processor, perform a method in situ in the etching chamber, the method comprising:   vertically growing oxide on the features of the mask layer by concurrently
 depositing the oxide on the features using the precursor gas and the oxygen-containing gas, and 
 etching side protrusions of the oxide vertically overlapping the openings using the fluorine-containing gas; and 
   etching the underlying layer through the openings using the oxide as an etch mask.   
     
     
         17 . The plasma etching system of  claim 16 , further comprising:
 a bias power supply coupled to the substrate support and operatively coupled to the controller, the bias power supply being configured to supply bias power,   wherein vertically growing the oxide on the features of the mask layer further comprises applying the bias power to the substrate concurrently with depositing the oxide and etching the portions of the oxide.   
     
     
         18 . The plasma etching system of  claim 16 , further comprising:
 a source power supply operatively coupled to the etching chamber and the controller, the source power supply being configured to supply source power,   wherein etching the underlying layer comprises generating plasma using the source power, and   wherein vertically growing the oxide on the features of the mask layer further comprises coupling the source power to the etching chamber concurrently with depositing the oxide and etching the portions of the oxide.   
     
     
         19 . The plasma etching system of  claim 16 , wherein vertically growing the oxide and etching the underlying layer are alternated as part of a cycle. 
     
     
         20 . The plasma etching system of  claim 16 , wherein the precursor gas comprises tetrachlorosilane, the oxygen-containing gas comprises dioxygen, and the fluorine-containing gas comprises nitrogen trifluoride.